Conventionally known thermoelectric modules are made by alternately arranging a large number of p-type thermoelectric semiconductors (hereafter referred to as p-type semiconductors) and a large number of n-type thermoelectric semiconductors (hereafter referred to as n-type semiconductors) in series and connecting adjacent p-type and n-type semiconductors to each other through an electrode to form a p-n junction structure. The p-n junction structure is then combined with a heat absorbing body to serve as a heat exchanger (see Japanese Patent Application Laid-Open No. 63-262075).
However, a conventional thermoelectric module has numerous shortcomings. For example, the temperature distribution of its heat absorbing body easily becomes non-uniform and such that if a temperature difference is produced between p-type and n-type semiconductor junctions present at different positions in the same module, the internal resistance between p-n junctions in the thermoelectric module varies. This variation of the internal resistance causes the entire internal resistance of the thermoelectric module to increase, such that the thermoelectric performance of the module deteriorates. This problem occurs not only in the same module but also between different modules when using a plurality of thermoelectric modules.
Moreover, because an electrode in conventional modules is soldered with a p-type or n-type semiconductor and the solder has a relatively low melting point, the operating temperature of the thermoelectric module is relatively low. It is therefore impossible to completely improve the thermoelectric performance of the thermoelectric module.
Furthermore, the production cost of conventional thermoelectric modules is high due to the complexity of p-n junction structures and the large number of parts that are required.
In addition, such a conventional thermoelectric module lacks in reliability because the operation of the module stops when even one of many p-n junctions is disconnected, since the junctions are connected in series.
A need therefore exists for a thermoelectric module having a high thermoelectric performance, simple structure, low production cost, and high reliability. The present invention fulfills these needs, and provides further related advantages.